This present application relates to combustors in gas turbine engines and related combustion systems or devices. More specifically, but not by way of limitation, the present application relates to using event stream processing techniques for detecting blowout precursors in combustors and related combustion systems and devices.
Combustors have long been used to burn a fuel/air mixture that is ultimately used to generate thrust, produce power, supply heat for some industrial process, or other application. In these systems, an important performance metric is for the flame to remain stable in the combustor over a range of flow rates, pressures, and fuel/air ratios. At certain conditions, however, the flame may blow out within the combustor, so that no flame exists. The problem of such a “blowout”, as the condition will be referred to herein, has long limited allowable flow velocities through engines, particularly in systems such as gas turbines which must operate at high flow rates and/or low pressures. The problem of blowout, however, has become increasingly more severe in a range of combustion devices, as they are required to meet stringent emissions legislation, severe operability constraints, and achieve better performance.
As will be appreciated, the problem of flame blowout can occur in combustors of land-based turbine engines, aeronautical turbine engines, afterburners, industrial processing devices, or any other combustor device. With respect to land-based turbine engines, operators of such engines attempt to run the engine near flame blowout conditions, known as the lean blowout line. An advantage of operating so close to the blowout line is that nitrous oxide emissions are significantly lowered. The trade-off, however, is an increased likelihood of flame blowout occurring. In the land-based systems, a blowout event may require a potentially lengthy system shut down and restart, resulting in economic consequences to the power plant owner. Further, in an aeronautical setting, blowout is a particular concern during fast engine transients, such as when rapid acceleration or deceleration of the engine is attempted. If the flame blows out in a commercial airplane, there are obvious safety concerns for the passengers, though most engines can be re-ignited in-flight. However, because of the magnitude of the possible consequences, engine designers include substantial safety margins into the engines to avoid these events, often at the cost of reduced performance.
The need to avoid blowout in combustors often causes designers to sacrifice performance in other areas. In particular, because there is always some uncertainty in the exact conditions under which blowout occurs, extra margin must be built into the design. In such systems, performance could be improved—and the occurrence of blowout more effectively avoided—if systems and methods existed to monitor the proximity of the system to blowout. Thus, there exists a need in the industry for systems and methods for accurately predicting flame blowout conditions on various types of combustors.